Overboring cylinder sleeve/liner?

[NAM VET]

Was over last week to the machine shop, he showed me my engine's internals, noted the stock bore and what crank and rod bearings I need to order. Pointed out my sleeves/liners in all six cylinders, and I asked if he can bore them out to his recommended .030 overbore. He reassured me no problem, and I have already ordered the .030 pistons and the necessary bearings. But reflecting now that the sleeve walls look pretty thin, just guessing perhaps about 80 thousands or so, that it would be best to just order new stock bore liners and use new stock bore pistons, instead of boring my present stock sleeves out. But looking around, I see VPW has sleeves that are .020 already overbore. So I am "only" going .010 over new ones anyway. Then too, my present sleeves look tight, and there is always a risk I suppose when replacing sleeves that they may slip (as noted on this forum in another's engine), and it would be best to leave well enough alone. I have read that there are opinions here that sleeves somehow are "better" in these motors than just an iron block bore. I don't really have much choice I suppose to go "new" and will have my liners go .030 overbore.

Any experience with my concern?

NV
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[Carter]

The engine I have in my truck had sleeves already installed but also needed to be opened up to .030 which I had the shop do and I have had no trouble with the sleeves displacing. I have removed the head several times since the shop work was done years ago and have never seen a sign of movement.

[NAM VET]

Reassuring, good to hear. And got your PM, and have replied, if it doesn't get to you, let me know.

N V

[just me]

If they are installed correctly and you don't overheat it, they won't move.

[Carter]

And got your PM, and have replied, if it doesn't get to you, let me know.

N V

Not yet.

[MSeriesRebuild]

What you have in the photo appears to be the typical sleeve job as seen in government rebuilt engines. Yes sleeves installed that way can be a problem if bored too thin. This is based on my observations over years. The proper way to install any sleeve is as follows: When over boring for sleeve installation, NEVER bore the cylinder all the way through. Always leave a small margin in the bottom of the bore for the new sleeve to press down against. During the final sleeve finishing process, this small area can be honed to match the sleeve bore size. The purpose in leaving this margin at the bottom is to prevent the new sleeve from ever slipping downward. This is an especially important step if the need ever arises to bore the sleeves to an oversize later, (which is your exact question now). The fact is simple, when over boring a sleeve, as the sleeve wall gets thinner, it looses some of its grip against the block cylinder wall, increasing the chance of slippage. I've looked at the quality of workmanship in many a government rebuilt 230 engine, can't say I ever saw one that didn't leave something to be desired. No way to know how snug your liners are at present, or how snug they may be after boring to the desired oversize. It is a chance you take, or try something else in hopes of being able to improve the situation. From where you are at present, the big question is this. How tight are the current sleeves pressed in?? Your machinist would be right in saying boring the sleeve is a perfect option, if he knew the workmanship specifics of the sleeve job you have, or the sleeves were pressed in against a margin left in the bore as described above. Beyond that, (simply no way to know these specifics), both you as the customer and he as the service provider really can not know for absolute whether boring the sleeves is a good option. Here is what I would do if I were building this engine; option #1, sleeves are available in many dimensional variations. I would check to see if sleeves were available with a slightly thicker wall, (larger OD) if sleeve of this spec can be had, then you can press the old sleeves out, bore the cylinder to the necessary diameter to install the slightly thicker wall sleeve, leaving a bottom bore margin, and go back to the standard bore diameter. A better than new engine can be built according to option #1, it is an absolute fact that an engine with cast iron sleeves will run and perform better than an engine that has not had sleeves installed. Option #2, if the specifics of option #1 are not possible, you are basically right back where you are now. Bore the sleeves and take a chance hoping for the best, it may be ok, but honestly it isn't something I would do as a service provider and provide warranty against any damage that could result from possible sleeve slippage. You and your machinist are able to inspect what you have; I'm talking based on what I have seen in engines we have dealt with, not from inspecting your current situation. If your guy is willing to bore it, feels good about no issues and is willing to put warranty on it, then maybe you have your answer. Usually good common sense when you look at these situations goes a long way.

[Kaegi]

I would bore the sleeves that are in there if the engine has been running well with them for many miles. They were obviously installed well if so. I disagree that a sleeve is somehow better than a block. Why would it be better? just more risk of water leaks. The Molybdenum content in Chrysler blocks back then if very high. these are very good castings. Obviously they are still being run all over the world in trucks and machinery without sleeves. I have personally put at least 250K miles on just a few of these engines and rebuilt a bunch more. and my shoe contains lots of lead. I only installed a couple sleeves on bores that were too grooved from piston snap rings or pins to bore. sleeving a whole block "just because' is a waste of time and money.

[MSeriesRebuild]

I would bore the sleeves that are in there if the engine has been running well with them for many miles. They were obviously installed well if so. I disagree that a sleeve is somehow better than a block. Why would it be better? just more risk of water leaks. The Molybdenum content in Chrysler blocks back then if very high. these are very good castings. Obviously they are still being run all over the world in trucks and machinery without sleeves. I have personally put at least 250K miles on just a few of these engines and rebuilt a bunch more. and my shoe contains lots of lead. I only installed a couple sleeves on bores that were too grooved from piston snap rings or pins to bore. sleeving a whole block "just because' is a waste of time and money.

I pretty much expected someone would respond like this. In an effort to help you understand better, I'm not suggesting a block be sleeved just because. We don't install sleeves in 230 engines unless there is a need, some of which you mentioned. There is much more to the story of why it is a fact a sleeved engine does run and perform better than those that aren't. Can't get into all that here; I will say this and leave it there. You have heard the old line "seeing is believing", this is a great example of it. If you saw two identical engines side by side on test stands, identical in EVERY way except one had sleeved bores, the other did not, you too would see. I was as skeptical as you are right now years ago when I saw this done by a major veteran engine builder. He was 150% right, we tried out his theory later, it only took one build to make me a believer. So this trick was not my discovery, I only followed the advice of a seasoned veteran in the business who had proven it and knew his stuff. People called him nuts then too.